Structure and enhanced properties of perovskite PNN-PZN-PMN-PZ-PT ceramics by Ni and ferroelectric Mg doping

Perovskite ferroelectric oxide ceramics of 0.1Pb(Ni(1/3)Nb(2/3))O(3)-0.35Pb(Zn(1/3)Nb(2/3))O(3)-0.15Pb(Mg(1/3)Nb(2/3))O(3)-0.1PbZrO(3)-0.3PbTiO(3) (0.10PNN-0.35PZN-0.15PMN-0.10PZ-0.30PT) with excess MgO and NiO were investigated in this work. The effects of the excess MgO and NiO doping on the ceramic structure, density, dielectric, ferroelectric and piezoelectric properties were studied. The chemical states of nickel were examined using X-ray photoelectron spectroscopy (XPS). Both XPS experimental results and theoretical analyses on the basis of ionic packing indicated that the excess valence-two ions substituted the A-sites in the ABO(3) perovskite structure. By completely eliminating the pyrochlore phase and enhancing densification with the excess NiO and MgO, improved piezoelectric coefficient d(33) up to 459 pC/N, higher ferroelectric remnant polarization and dielectric constant were demonstrated when sintered at temperature as low as 850-950 degrees C. (C) 2008 Elsevier Ltd and Techna Group S.r.l. All rights reserved.